An assessment of the microbial quality of “döner kebab” during cold storage: Effects of different packaging methods and microwave heating before consumption

Abstract

In the current study, döner kebabs packed with different packaging methods (air packaging [AP], modified atmosphere packaging [MAP], vacuum packaging [VP] and sous vide packaging [SVP]) were evaluated for their microbial quality during storage at 4 °C. In addition, the effect of microwave heating before consumption on the microbial quality of döner kebabs was also investigated. Total mesophilic aerobic bacteria and total psycrophilic aerobic bacteria counts of döner kebabs increased during storage and reached to 6.48, 8.27, 8.15, 3.96 and 5.58, 8.53, 8.63, <1.00 log cfu/g in AP (9th day), MAP (29th day), VP (29th day) and SVP (99th day) groups, respectively. Although coliform, Escherichia coli and Staphylococcus aureus counts of döner kebabs were below 3 MPN/g, 3 MPN/g, 2 log cfu/g in all groups, respectively; no Clostridium perfringens and Listeria monocytogenes was detected in any of the groups during storage. Microwave heating was found effective on reducing the microbial load of döner kebabs. It was concluded that without any additional preservation techniques, the SVP prolonged the shelf life of döner kebabs more than 20, 6, and 5 times comparing to AP, MAP, and VP groups, respectively. Practical applications Döner kebab is a meat product which is very convenient for microbial growth due to its nutritional and chemical composition. Döner kebab that cannot be sold immediately after production causes high economic losses since the shelf life of döner kebab is very short after cooking. Therefore, it requires additional preservation techniques in order to prevent the economic losses after cooking and to have the opportunity of secure serving of it where döner kebab oven is not present. In the current study, sous vide (SV) applied döner kebabs protected their microbiological quality at least 100 days at 4 °C without any additional preservation techniques and application of SV after cooking provided döner kebabs with a longer shelf life comparing to air packaging, modified atmosphere packaging and vacuum packaging methods. Besides, microwave heating was applied to döner kebabs in order to simulate the conditions of consumption. Microwave heating before consumption significantly reduced the microbial load of döner kebabs.